1. Field of the Invention
The present invention relates to a method for purifying nucleic acids to obtain nucleic acids that are used as a sample in the case that various procedures are conducted using nucleic acids.
2. Description of the Related Art
As a method for purifying nucleic acids, a method comprising breaking down proteins by means of enzymes such as proteinases, and then removing the decomposed proteins and components of fat-soluble contaminants by conducting a phenol-chloroform extraction, has been generally used.
Besides the above method, a method comprising allowing nucleic acids to be absorbed on glass beads and removing components other than nucleic acids, a method for purifying nucleic acids by filtering only nucleic acids using a filter, and others, have been developed.
However, nucleic acids with high purity cannot be obtained from feces by the above-mentioned methods. By the method conducting the phenol-chloroform extraction after treating the feces with the enzymes using the proteinases, contaminants other than the fat-soluble contaminants cannot be removed. By the method comprising allowing the nucleic acids to be absorbed on the glass beads, contaminants in the feces inhibit absorption of the nucleic acids on the glass beads. By the method using the filer, filtration cannot be accomplished due to clogging of the filter with contaminants in the feces.
Indeed, after a process for purifying nucleic acids was performed by treating feces as a sample with enzymes using proteinases followed by conducting the phenol-chloroform extraction, precipitates of the nucleic acids were obtained by an ethanol precipitation method. As a result, the precipitates were yellowish or brownish. This result indicates that contaminants in the feces are not removed and purification of the nucleic acids is not accomplished in high purity.
An object of the present invention is to provide a method capable of removing contaminants other than nucleic acids derived from feces at high efficiency and thereby obtaining nucleic acids with high purity, although it is difficult to purify the nucleic acids in high purity from feces.
In order to solve the subjects described above, the present invention is a method for purifying nucleic acids from feces, wherein a feces sample is purified using a quaternary ammonium salt.
The present invention is the method for purifying nucleic acids, wherein an organic solvent is also used.
The present invention is the method for purifying nucleic acids, wherein the quaternary ammonium salt selected from the group consisting of hexadecyltrimethylammonium bromide, hexadecylpyridinium chloride, hexadimethrine bromide, hexafluorenium bromide and methylthiazolium bromide is used as the quaternary ammonium salt.
The present invention is the method for purifying nucleic acids, wherein the quaternary ammonium salt is used by being dissolved into water or a pH buffer solution.
Further, the present invention is the method for purifying nucleic acids, wherein at least one organic solvent selected from the group consisting of chloroform, carbon tetrachloride, phenol, benzene, ethers, acetone and alcohols is used as the organic solvent.
According to the present invention, nucleic acids with high purity can be obtained from feces, although it is difficult to obtain purified nucleic acids from the feces.